1. Field of the Invention
The invention relates to a rechargeable battery and a battery module using the same, and more particularly, to a rechargeable battery of which positive and negative electrodes can be readily discriminated from each other in a short time and a manufacturing process can be simplified, and a battery module using the same.
2. Description of the Related Art
Generally, a battery module includes a few or several tens rechargeable batteries connected with one another. The rechargeable battery can be repeatedly charged and discharged because its chemical and electrical energy conversion is reversible. Recently, more and more mobile wireless electronic products are being developed, and necessity of the rechargeable battery having a high energy density increases as their sizes are miniaturized and their weights are reduced.
Widely used batteries include a nickel-cadmium battery, a nickel-hydrogen battery, a lithium battery, and the like. Particularly, the lithium rechargeable battery has an operation voltage of 3.6 V, which is triple that of the nickel-cadmium battery or the nickel-hydrogen battery, and also has a high energy density per unit weight. Therefore, the lithium rechargeable battery is being rapidly popularized as a power supply of mobile electronic devices. Such a lithium rechargeable battery can be classified into a lithium ion rechargeable battery, a lithium ion polymer battery, and a lithium polymer battery. While the lithium polymer battery is nearly similar to the lithium ion rechargeable battery, electrolyte of the lithium ion rechargeable battery is substituted with polymer. It contributes to flexibility of design in the shape as well as higher safety.
A typical rechargeable battery includes an electrode assembly having a positive electrode, a negative electrode, and a separator interposed therebetween, a casing providing a space for storing the electrode assembly, and a cap plate combined with the casing to seal the electrode assembly. Each of the positive and negative electrodes includes a coated portion where an activation material is coated and an uncoated portion where the activation material is not coated. The uncoated portion is provided to collect the current generated in the positive and negative electrodes, and a conductive tap is attached thereto. The conductive tap induces the current generated in the positive and negative electrodes to the positive and negative terminals, respectively. The rechargeable battery may be manufactured in a variety of shapes such as cylindrical, rectangular, and pouch types depending on the shapes of the electrode assembly and the casing.
The battery module having a plurality of rechargeable batteries connected with one another as described above is being widely used as a power supply for driving motors of portable miniaturized electronic devices such as mobile phones, personal computers, and camcorders, and hybrid electric vehicles.
When the rechargeable batteries are combined with one another to provide a battery module, they are arranged in series such that a positive electrode terminal of one of the rechargeable batteries and a negative electrode terminal of the adjacent rechargeable battery face the same direction. Then, the positive and negative electrode terminals are connected with each other using an interconnection member. The interconnection member may be fixed by a fastening mechanism such as a nut.
During a process of manufacturing the battery module, the positive and negative electrodes of the rechargeable batteries should be readily discriminated in a short time. If they cannot be readily discriminated, the interconnection member may be erroneously inserted. Therefore, the manufacturing process should be very carefully performed. As a result, it took a long time to manufacture the battery module, and thus, productivity was degraded.